The executive producer for “Arrow” Marc Guggenheim recently talked to E! Online where he spilled the beans about Sara Lance’s resurrection. He confirmed that Sara will be appearing in “Arrow” season 4 before we see her as the White Canary on “Legends of Tomorrow.”
Beth: Please tell me the White Canary will be on Arrow this season!
“Your wish, our command because we have it on good authority that Sara’s resurrection will begin on Arrow before Legends of Tomorrow kicks off. “The White Canary will be launched in the first few episodes of Arrow,” boss Marc Guggenheim spills. “4×08, our typical crossover episode, will be doing a lot of heavy-lifting in terms of getting the Legends of Tomorrow characters set up and also seeing where they are with relation to The Flash. It’s a big episode.” Huzzah!” Guggenheim said.
An official premiere date for “Legends of Tomorrow” has yet to be announced but it’s likely to arrive during mid-season on the CW. As you can see above Guggenheim mentions episode 8 of “Arrow” season 4 will work to set the show up.
https://www.youtube.com/watch?v=4MubNoWQiSc